The present invention relates in general to water disinfection for human consumption. More particularly, the invention relates to low cost water filtration and disinfection to provide drinking water in situations where resources are limited.
In developing countries, drinking water is often difficult to obtain. Currently, every hour, more than four hundred children in the developing world die from water-borne diseases. Ordinarily, women and children haul water from open wells, rivers or lakes for daily use. They also are primarily responsible for gathering firewood. It is simply not feasible for them to gather enough wood to boil their drinking water, and chemical disinfection is cumbersome and often impractical in communities without a water system and without a supply chain of chemicals for disinfection. Diseases like cholera often spread through contaminated water. Vaccines are expensive and practically difficult to administer on a widespread basis. Furthermore, mutant strains of old diseases have made current vaccines ineffective. Similar concerns occur whenever people are camping, or in any post-disaster situations. Thus, the need for a portable, easy to use, but effective water disinfector exists around the world.
A wide variety of water disinfection systems are currently available. Typical systems, however, are unsuitable for disinfecting drinking water in developing countries. Many systems, for example, are designed to treat industrial water use or large-scale (e.g., municipal) water supply. These systems tend to be impractically expensive and complex for small scale use, e.g., for use by less than a dozen persons. Other systems are developed for household use in industrial countries or for developing country populations with a pressurized tap water supply. In this case, the systems tend to operate under pressure from the municipal water supply, and therefore are unsuitable for use in places without running water. Furthermore, such systems tend not to address some of the pathogens commonly found in developing countries, especially in sub-tropical and tropical climates.
Accordingly, a need exists for small-scale systems and methods for safe, effective provision of drinking water. Desirably, such systems and methods should be portable and inexpensive enough to be practical for use in remote locations, particularly in developing countries.
In accordance with one aspect of the present invention, a water disinfector is provided. The disinfector includes a gravity-driven feed water delivery system that defines a water flow path from an upstream inlet to a downstream outlet. A ceramic filter is positioned within the water flow path, while an ultraviolet light source is positioned to irradiate water downstream of the ceramic filter.
In accordance with another aspect of the present invention, a method is provided for disinfecting water. The method includes feeding water into a water delivery system. The water is driven by gravity through a ceramic filter to produce filtered water. This filtered water is then exposed to ultraviolet light within the water delivery system, downstream of the ceramic filter.
In the illustrated embodiments, the ceramic filter is a cylindrical xe2x80x9ccandlexe2x80x9d filter with a bore extending partially therethrough. The filter is placed over an outlet in a container, and feed water poured into the container. This feed water then percolates through the filter, and is thence carried along a flow path through the outlet to a storage container. In several embodiments, the filtered water is disinfected by ultraviolet irradiation along the flow path. Irradiating the water in batches stored in the storage container can also disinfect the filtered water.
The invention represents an advancement in providing safe water to the people of developing countries. A very low-power UV lamp and a low cost ceramic filter enable provision of drinking water with only a small expenditure of electrical energy from virtually any fresh water source, even of uncertain or compromised biological quality. Gravity-driven operation keeps costs low while facilitating longer UV exposure times for the water, thus facilitating complete disinfection. The unique qualities of the water disinfector allows people in rural and underdeveloped regions of the world to enjoy that advantages of safe water at a low cost. Accordingly, decreases can be realized in infant deaths and general illness in such communities.